Submitted to: International Journal of Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 23, 2007
Publication Date: January 2, 2009
Citation: Singh, M., Byars, J.A. 2009. Starch-Lipid Composites in Plain Set Yogurt. International Journal of Food Science and Technology. 44(1):106-110. Interpretive Summary: Yogurt is formed by the fermentation of the lactose in milk and the formation of the gel structure. Syneresis is a defect in yogurt in which the liquid separates from the yogurt and forms a layer on the top during storage. This is caused by the weakening of the yogurt gel. The objective of this experiment was to study the effects of FanteskTM on the gel structure. FanteskTM at different levels (0-4%) was used to replace the milk solids (0-40%) for the preparation of yogurts. It was found that addition of FanteskTM did not inhibit the fermentation and formation of the gel structure. FanteskTM levels of 4% and higher resulted in no syneresis in yogurt samples stored for three weeks. This study will benefit the yogurt industry by offering alternatives.
Technical Abstract: Starch-lipid composites (0.5, 1, 2, 3, and 4%) were used to replace milk solids (5, 10, 20, 30, 40%) in yogurt mixes. The effects of the starch-lipid composites on the yogurt fermentations and rheology were studied. The rate of fermentation was evaluated by the change of pH every two minutes during the fermentation of yogurt. The syneresis of yogurt was observed over three weeks of storage. Controlled stress rheometer was used to obtain small amplitude oscillatory shear flow measurements of the storage modulus G’, the loss modulus G”, and the loss tangent tan delta (= G”/G’) using a vane geometry. Yogurt mixes with milk solids partially replaced by starch-lipid composites (SLCs) fermented at a similar rate as those with no milks solids replaced. Initial viscosity was higher for yogurt mixes with higher levels of SLCs. The higher initial viscosity did not affect the gel structure. The addition of SLCs above a level of 3% strengthened the gel and resulted in no syneresis for yogurt samples stored for three weeks at 4 deg C.